Raw and Ledger
The bottom two layers of the stack do one job together: turn messy financial evidence into deterministic, structured records with provenance back to source.
Raw Layer
The Raw Layer ingests financial evidence verbatim from authorized sources.
Sources
Banks and processors
Plaid, direct bank APIs, Stripe, Adyen
Custodians and brokerages
Brokerage feeds, custodian APIs
On-chain
Wallets via Alchemy, contract event streams
ERPs
NetSuite, SAP, Dynamics
Accounting platforms
QuickBooks, Xero
Payroll
Major payroll providers
Documents
Email-attached invoices and receipts, CSV/PDF uploads
Storage Rules
Artifacts are content-addressed by SHA-256 and stored under tenant-prefixed Azure Blob paths. Source credentials, not every raw artifact, are encrypted at the application boundary with the global AES-256-GCM source-credential key from shared/src/crypto/credential-key-provider.ts.
Identifier
sha256:<hex> over canonical bytes
Encryption
Source credentials use AES-256-GCM with a global key today
Storage
Azure Blob with versioning, tenant prefixes, and lifecycle policies
Retention
Per-tenant, configurable per source
Nothing is interpreted at this layer. The Raw Layer's only job is to be a lossless, replayable record. If the extraction logic changes, every higher layer can be rebuilt deterministically from Raw.
Ledger Layer
The Ledger Layer normalizes raw evidence into standard linkable objects.
Record Types
transactions
Money movements between accounts
balances
Point-in-time and rolling balances
accounts
Tenant-side and counterparty accounts
counterparties
Vendors, customers, employees
invoices
Billed amounts, due dates, line items
obligations
Subscriptions, recurring charges, contracts
cash_flows
Aggregations and forecasts
assets and liabilities
Holdings and debts
permissions
Authorizations affecting the Ledger
events
Lifecycle events tied to records
Provenance on Every Record
Every Ledger record carries:
raw_refs
The Raw artifact hashes that produced it
extractor_version
The deterministic extractor that produced it
confidence
A calibrated score from 0 to 1
supersedes
Optional pointer to the record this corrects
Immutability
Records are immutable and append-only. Corrections are written as superseding records that reference what they correct.
The history is preserved. Any reader can replay the chain to see how the value evolved.
Why Ledger Sits Between Raw and Wiki
LLMs are excellent at language and pattern recognition and unreliable at arithmetic, deduplication, and reconciliation.
Arithmetic, deduplication, reconciliation
Ledger (deterministic)
Fluent reasoning, narrative answers
Wiki (LLM-driven, citation-backed)
The Wiki is the place for fluent reasoning, not the source of financial truth. Ledger enforces a deterministic, machine-verifiable structure first, so Wiki always reasons over verified facts rather than reinterpreting raw documents on every query.
This is the same separation that exists in any serious system between the database and the cache. Brain's Ledger is the database; the Wiki is the reasoning surface that points back to it.
What's Next
Last updated